fix cert session issue

Author: Graeme22

tastytrade/__init__.py

@@ -4,7 +4,7 @@
 BACKTEST_URL = "https://backtester.vast.tastyworks.com"
 CERT_URL = "https://api.cert.tastyworks.com"
 VAST_URL = "https://vast.tastyworks.com"
-VERSION = "9.12"
+VERSION = "9.13"
 
 __version__ = VERSION
 version_str = f"tastyware/tastytrade:v{VERSION}"

tastytrade/session.py

@@ -362,8 +362,9 @@ def __init__(
         #: URL for dxfeed websocket
         self.dxlink_url = data["dxlink-url"]
         #: expiration for streamer token
-        self.streamer_expiration = datetime.fromisoformat(
-            data["expires-at"].replace("Z", "+00:00")
+        exp = data.get("expires-at")
+        self.streamer_expiration = (
+            datetime.fromisoformat(exp.replace("Z", "+00:00")) if exp else None
         )
 
     def __enter__(self):
@@ -479,7 +480,11 @@ def serialize(self) -> str:
         del attrs["sync_client"]
         attrs["user"] = attrs["user"].model_dump()
         attrs["session_expiration"] = self.session_expiration.strftime(_fmt)
-        attrs["streamer_expiration"] = self.streamer_expiration.strftime(_fmt)
+        attrs["streamer_expiration"] = (
+            self.streamer_expiration.strftime(_fmt)
+            if self.streamer_expiration
+            else None
+        )
         return json.dumps(attrs)
 
     @classmethod
@@ -500,9 +505,8 @@ def deserialize(cls, serialized: str) -> Self:
         self.session_expiration = datetime.strptime(
             deserialized["session_expiration"], _fmt
         )
-        self.streamer_expiration = datetime.strptime(
-            deserialized["streamer_expiration"], _fmt
-        )
+        exp = deserialized.get("streamer_expiration")
+        self.streamer_expiration = datetime.strptime(exp, _fmt) if exp else None
         self.sync_client = Client(base_url=base_url, headers=headers, proxy=self.proxy)
         self.async_client = AsyncClient(
             base_url=base_url, headers=headers, proxy=self.proxy

tests/test_session.py

@@ -1,3 +1,5 @@
+import os
+
 import pytest
 from proxy import TestCase
 
@@ -46,3 +48,11 @@ def test_session_with_proxy(self):
         )
         assert session.validate()
         session.destroy()
+
+
+def test_cert_session():
+    username = os.getenv("TT_USERNAME_SANDBOX")
+    password = os.getenv("TT_PASSWORD_SANDBOX")
+    assert username and password
+    session = Session(username, password, is_test=True)
+    session.destroy()